Effective testing of humans for fitness for duty in the workplace is essential.
This invention relates to targeting elements. In particular, the elements are humans targeted for testing for fitness-for-duty.
Different techniques for sampling elements are known. The most common technique is simple random sampling. However, simple random sampling has inefficiencies. For a low sampling rate, there remains a high percentage of a population untested in defined time periods. On the other hand, an excessive sampling rate, for instance at about a 300% rate, provides for approximately 95% of the population to be tested but approximately 58% of the elements are tested three or more times. Hence, there is either a relatively ineffective testing program which does not ensure that a high number of persons in a group are tested, or a high-cost, low-productivity program that tests many people too many times.
In most random sampling, only a relatively small fraction of the total number of elements in a target population is measured. From data on these elements, conclusions or inferences are drawn about attributes of the entire population. However, in some instances, the objective of the sampling is to ensure that the population is meeting certain standards. Instead of examining only a small fraction of the population once, it is necessary to examine small fractions of the population on a regular basis. The end result is that nearly all of the population may be sampled over some period of time.
An area of sampling that requires a nearly complete enumeration of the population is the concern for public safety and employee safety in many businesses today. The reason for this concern is the emerging information about subtle yet long-lasting after-effects of drug use, which may go undetected by supervisors. This has raised the speculation that decision-making in emergency situations may be hampered by off-duty drug use. In response to this concern, fitness-for-duty drug screening urinalysis programs are being developed. In order to implement programs of this type, many businesses are beginning to conduct random drug testing throughout the year in addition to the more common pre-employment drug testing of applicants.
To address fitness-for-duty in the workplace, sampling must be conducted in such a manner as to ensure that the population is meeting certain standards. Instead of examining only a small fraction of the population once, it is necessary to examine small fractions of the population on a regular basis.
The prevalent approach to random drug testing is to use simple random sampling with replacement each time a random selection is made. The benefit of this approach is that each time a selection is made, all employees are equally likely to be selected. Repeated testing is needed to ensure that a screening program will be an effective deterrent against drug use.
However, there is also an adverse element to repeated use of simple random sampling. Depending upon the percentage of employees being chosen for testing, one of the following scenarios will occur:
(1) If the sampling rate is set high so as to minimize the probability of not choosing an employee during the year, then there also is a high repeat selection of some employees. PA1 (2) If the sampling rate is lowered in order to reduce the high amount of repeat selection, then the probability of not choosing an employee during the year increases. PA1 (a) establishing a first data base constituted by essentially all the elements of the defined group, PA1 (b) establishing a second data base with initially all the elements of the first data base, PA1 (c) selecting a first element set from the first data base and thereafter replacing the selected first element set in the data base so as to maintain the first data base essentially unchanged, PA1 (d) removing from the second data base any element set existing in that data base selected from the first data base, PA1 (e) selecting a second element set from the second data base, PA1 (f) removing from the second data base element set selected from the second data base, and PA1 (g) defining the first element set from the first data base and the second element set from the second data base as the target elements in the range.
This invention is directed at providing a technique for overcoming the difficulties with simple random sampling. An advantage that this technique brings to a fitness-for-duty program is a balance between company standards and productivity.